We might want to consider a different configuration strategy here, assuming one would never want to configure a specific interface twice.  First, starting a sequence right after netmap defines the netmap parameter as a sequence, limiting the ability to add new non interface values to it.  Second, having the interfaces as a sequence will make it harder to provide overrides from the command line if we decided to do so (some discussion here https://redmine.openinfosecfoundation.org/issues/921), as that would involve including the sequence index from the command line, which may not be known.

We may want to consider something like:

```
netmap:
  defaults:
    threads: 1
  interfaces:
    eth2:
      threads: 1
      #copy-mode: tap
      #copy-iface: eth3
    eth3:
      threads: 1
      #copy-mode: tap
      #copy-iface: eth2
```

Or if a sequence really is desired, nest it down one level so netmap can contain values that are not sequence items at a later time:

```
netmap:
  defaults:
    threads: 1
  interfaces:
    - eth2:
        threads: 1
    - eth3:
        threads: 1
```

But I don't think a sequence is really needed here unless there is a valid reason to specify an interface more than once.